Conventionally, in a rotary working machine such as power shovel, a rotating table frame is generally arranged on a traveling device, a working machine including a boom and arm and an attachment such as a bucket is attached to the front part of the rotating table frame, and an engine, a counter weight, and the like are arranged at the rear part of the rotating table frame. A step provided with an operation lever for hydraulic actuator operation, an operation pedal, and the like is arranged at the front part of the rotating table frame, and a control valve connected to the operation pedal and the like at the lower side of the step to perform drive control of the hydraulic actuator is arranged horizontally (see e.g., Patent Document 1).
However, in the rotary working machine as in the prior art, since the control valve is arranged on the rotating table frame in a horizontal state, the space at the front and the back of the control valve becomes narrow, and such portion cannot be effectively used. The distance between the control valve and the operation lever or the operation pedal becomes long, and the link mechanism for connecting the same has a complex configuration, whereby a great number of components are required and reduction in cost is difficult to achieve.    Japanese Laid-Open Patent Publication No. 2003-20683